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Magnetic nanoparticles of Ga‐substituted ε‐Fe 2 O 3 for biomedical applications: Magnetic properties, transverse relaxivity, and effects of silica‐coated particles on cytoskeletal networks
Author(s) -
Královec Karel,
Havelek Radim,
Koutová Darja,
Veverka Pavel,
Kubíčková Lenka,
Brázda Petr,
Kohout Jaroslav,
Herynek Vít,
Vosmanská Magda,
Kaman Ondřej
Publication year - 2020
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.36926
Subject(s) - materials science , cytoskeleton , superparamagnetism , mesoporous silica , nanoparticle , focal adhesion , nanotechnology , mesoporous material , shell (structure) , actin , magnetization , composite material , cell , chemistry , magnetic field , organic chemistry , biochemistry , physics , quantum mechanics , catalysis
Magnetic nanoparticles of ε‐Fe 1.76 Ga 0.24 O 3 with the volume‐weighted mean size of 17 nm were prepared by thermal treatment of a mesoporous silica template impregnated with metal nitrates and were coated with silica shell of four different thicknesses in the range 6–24 nm. The bare particles exhibited higher magnetization than the undoped compound, 22.4 Am 2 kg −1 at 300 K, and were characterized by blocked state with the coercivity of 1.2 T at 300 K, being thus the very opposite of superparamagnetic iron oxides. The relaxometric study of the silica‐coated samples at 0.47 T revealed promising properties for MRI, specifically, transverse relaxivity of 89–168 s −1 mmol(f.u.) −1 L depending on the shell thickness was observed. We investigated the effects of the silica‐coated nanoparticles on human A549 and MCF‐7 cells. Cell viability, proliferation, cell cycle distribution, and the arrangement of actin cytoskeleton were assessed, as well as formation and maturation of focal adhesions. Our study revealed that high concentrations of silica‐coated particles with larger shell thicknesses of 16–24 nm interfere with the actin cytoskeletal networks, inducing thus morphological changes. Consequently, the focal adhesion areas were significantly decreased, resulting in impaired cell adhesion.